Subject wise Technical Mechanical Interview Questions By S k Mondal
Technical Questions Subject wise
Type of technical questions asked will be from basics. Your favorite subjects will be asked and they start from there.
Strength of Materials
- What do you mean by uniform strength in a beam?
- What is difference between pure shear and simple (normal) shear?
- Is it possible that decrease in area gives a decrease in stress?
- Whether shear stresses are always parallel to shear forces?
- By which experiment, you find it toughness of material.
- Distinguish between direct stress & bending stress.
- What do you mean by Torsional rigidity & lateral rigidity?
- Define “slenderness ratio”. How it is used in long and short column?
Machine Design
- What are rolling contact bearing?
- What are the antifriction bearings?
- What is stress concentration factor?
- What is the bolt of uniform strength?
- What is the difference Static Load carrying capacity & Dynamic Load carrying capacity?
- Why we are not using the unit joule for torque instead of N-m.
- What is Low cycle fatigue failure and High cycle fatigue failure? What are considerations of these while designing a machine?
- What is mechanical advantage?
- How trains take turns though there is no differential gear?
- Do you know epicyclical gear box? What is the practical application of epicyclical gear box?
- What is tooth profile? Which one is better?
Theory of Machines
- What is keneddy theorem?
- What is defect in Davis steering gear?
- Do we need a screw with efficiency less than 50%?
- What is backlash?
- What is damping ratio?
- Define Resonance.
- Define critical speed or whirling speed or whipping speed.
- What is machine? Giving example, Differentiate between a machine & structure.
- What is Mechanical advantage.

Thermodynamics
- What is availability function for a closed system?
- If it is possible that entropy of a system can decrease during a given process?
- What is dead state in thermodynamics?
- What is energy?
- What happens to triple point line when projected to P-T plane?
- What is compressibility factor and what is its value for Vander walls gases.
- What are initial conditions for formation of shock waves?
- What do you understand by choking in nozzle flows?
- Is it possible that pressure and velocity decreases simultaneously/
- Distinguish between “Available energy” & Availability?
- What is pure substances.
- What is critical point? What is the value f critical temperature, pressure & volume of water?
- What is sublimation curve, fusion curve & vaporization curve?
- What is Rayleigh Line & Fanno Line?
- What is normal shocks & when its occurs?
- What is High Grade Energy & Low Grade Energy?
Fluid Mechanics and Fluid Machinery
- What is the difference between impulse & reaction turbine.
- Explain unit speed, unit discharge unit power & specific speed.
- Explain NPSH, in which parameter it depends on.
- What is jet ratio?
- What is Deriaz turbine?
- Which turbine is good for tidal power plant?
- What is Navier-stroke equation.
- What are the significance of
- Mach number
- Weber number
Heat & Mass Transfer
- What is Newton’s Law of cooling.
- What is Recuperator & Regenerators?
- Whether fin can actually reduce heat transfer? is it possible? When?
- What is difference between Biot no. & Nusselt no?
- Which one is greater, thermal boundary layer or hydrodynamic boundary layer?
- What is film temperature in forced convection flow?
- What is fully developed region and where it is applicable?
- What is the critical radius of insulation, explain clearly in terms of thermal resistance and heat transfer rate?
- At what case do you recommend Fin?
- What is the difference between free convection & forced convection in what parameter forced & free convection depend.
Internal Combustion Engine
- What is the use of Carburetor in SI Engine, There is trend towards increases of injection system in Automobiles, Explain.
- Why Supercharging is not popular with SI Engines?
- What is performance number.
- Explain Knocking in SI Engine & Mention, the factor that tend to reduce Knocking?
- Explain the difference between Knocking in SI Engine & CI Engine?
- How does “Turbulence” differ from “Swirl”?
- Name some Antiknock additive and explain the Mechanism by which they reduce the knock?
Power Plant Engineering
- What is slip ratio in thermal power plant?
- In Pendant super heater whether parallel flow or counter flow heat exchange between steam and flue gases.
- What happens to mass flow in case of supersatured flow?
- Why clearance are provided in reciprocating compressor?
- Explain turbojet & Rocket Engine.
- What’s the advantage of compounding of steam turbine?
- What’s are boiler mounting & accessory.
- Draw the sketch of pulse jet engine. What are its main advantage & disadvantage?
- Explain working principal of scram jet engine, what is advantage over the ramjet?
- What are the advantage of nuclear power plants over thermal power plants.
- What is fast breeder reactor?
- What is circulation ratio and what is its range in power plant?
- One 2-row Curtis turbine is equivalent to how many reaction turbines for same value of blade velocity and angle of nozzle?
- What are thermal neutrons?
- What is breeding ratio?
- What is the application of jet and rocket technology? Which is used in missiles?
Refrigeration and Air-conditioning
- What is utility of comfort chart?
- What is wet compression?
- To maximize COP what should be the condition of vapour at suction to compression?
- What is the range of NBP (normal boiling point) in case of most refrigerants?
- Why COP of CO2 gas is less and still why it is used in transport refrigeration?
- What are the most crucial parts in reciprocating compressors?
- How compressors are selected based on type of refrigerant?
- What is correlation between wet bulb temperatures an adiabatic saturation temperature?
- Why isothermal compressor is Desirable?
- What is desirable property of ideal refrigerant?
- Define effective temperature & what is the optimum design condition for comfort for summer A/C?
Production Engineering
- Why arc is slowly extinguished in case of arc welding?
- Which inert gas is commonly used for thin work piece and which inert gas for thick work piece?
- What is friction welding?
- What is difference between brazing & braze welding?
- Why hole basis system is adopted in manufacturing?
- What is 3- 2-1 principle?
- Where diamond pin locator is used?
- How presses are rated?
- What is spring back?
- What is difference between fillet and corner radius?
- What are overhead costs?
- Why depreciation is to be taken into account in industrial management?
- Why breakeven point is important in any industry?
- What is sine bar?
- What is marginal cost and marginal revenue?
- What is shear and where it is provided in case of punching and blanking?
- What is angle of bite?
- What is extrusion ratio?
- What is gutter and where it is used?
- Which process is used for making nuclear reactor fuel rods?
- What is difference between Amorphous and crystalline solids?
- What are the various method of inspection of casting for internal & external defects?
- Why are allowances provided for in the production of patterns? What do they depend on?
- What is the deference between soldering & brazing?
- What is meant by solid-state welding explain.
- What is cold welding?
- Describe the principal behind resistance welding processes.
- What function should a lubricant perform in manufacturing process?
- Explain the difference between punching & blanking.
- Explain the difference between discontinuous chips and segment chips.
- Explain the different type of tool wear.
- What is difference between oblique & orthogonal cutting.
- What are the main difference between jig and fixture?
- What is AOQ
- What is LTPD
- What is Producer risk
- What is Consumer’s risk
- What is JIT approaches?
- What is group technology? What are its main advantages?
- Define the term “production & productivity.
- What is the significance of ISO 9000 series & 1400 series.
- What is artificial intelligence?
Material Science
- What is quazi-crystal?
- What do you understand by a free cutting steel? What elements are usually added to make a steel free cutting, & how they make the steel free cutting?
- Explain various method of hardening of steel?
- What do you understand by the term “Arrest point” in connecting with heat treatment of plain carbon steel?
- What influence does grain size have on the mechanical properties of metals.
- Describe the difference between brittle and ductile fracture.
- What is the difference between natural & artificial aging?
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